Conventional flexible grinding products have a layer of paper, plastic or fabric carrying abrasive particles such as aluminum oxide or silicon carbide. The grinding or abrasive particles are applied to one surface of the product utilizing a binding agent. The flexible grinding product is for instance suitable to be mounted onto a rotating or oscillating plate of a grinding machine.
One reason for deterioration of the grinding performance is due to blocking as abrasive dust tends to clog the grinding surface of the product.
An improvement of the durability of the grinding product by reducing the above clogging effect was achieved with a grinding product described in EP 0 779 851 A1. The grinding product comprises a cloth of woven or knitted fabric having projecting loops or thread parts. A grinding agent is applied as separate agglomerates to the surface of the grinding product. The expression “separate agglomerate” means that the grinding product does not comprise a continuous grinding or binding agent layer that would cover the surface of the cloth, but instead the grinding agent forms small point or line shaped accumulations. Thus the cloth has and maintains an open structure which allows to remove the grinding dust from the surface.
In the above-mentioned prior art, the grinding agent is applied onto the irregular surface of projecting threads or loops. This has the consequence that a non-uniform grinding result due to an irregular height-distribution of the grinding particles cannot be excluded, at least in critical applications. A very flexible impregnation and coating alleviates the surface failures but reduces the performance of the grinding product.
Further, it is difficult to calibrate the product using the back surface as a support in order to achieve a flattened or smooth grinding surface. This is particularly the case when the back surface of the cloth is irregular, possibly carrying threads or loops for attaching the grinding product to a grinding tool, and/or when the back surface is at least partly fixed by an impregnation.